Light-emitting display device

ABSTRACT

A light-emitting display device includes a substrate having a plurality of pixels. A first electrode is provided on the substrate for each pixel, and a pixel defining layer defines each of the pixels. The pixel defining layer has an opening to expose the first electrode. A charge injection layer is on the first electrode, and a surface processing layer is on the charge injection layer. The surface processing layer extends from inside the opening of the pixel defining layer to a top surface of the pixel defining layer. The surface processing layer including a plurality of grooves in a portion extending on the top surface of the pixel defining layer. A charge transport layer is on the surface processing layer, a light-emitting layer is on the charge transport layer, and a second electrode is on the light-emitting layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application based on pending application Ser. No.14/597,611, filed Jan. 15, 2015, the entire contents of which is herebyincorporated by reference.

Korean Patent Application No. 10-2014-0109588, filed on Aug. 22, 2014,and entitled: “Light-Emitting Display Device and Method of Manufacturingthe Same,” is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

One or more embodiments described herein relate to a light-emittingdisplay device, and a method of manufacturing a light-emitting displaydevice.

2. Description of the Related Art

An organic light-emitting display is self-luminous and has a wideviewing angle, high contrast ratio, and fast response time. Each pixelof this display has an organic light-emitting layer between an anodeelectrode and cathode electrode.

When positive and negative voltages are applied to these electrodes,holes move from the anode electrode to the organic light-emitting layervia a hole injection layer and a hole transport layer, and electronsmove from the cathode electrode to the organic light-emitting layer viaan electron injection layer and an electron transport layer. Theelectrons and holes recombine in the organic light-emitting layer togenerate excitons. As the excitons change from an excited state to aground state, the organic light-emitting layer emits light to form animage.

The organic light-emitting display may also include a pixel defininglayer having an opening that exposes the anode electrode of each pixel.The hole injection layer, the hole transport layer, the organiclight-emitting layer, the electron transport layer, the electroninjection layer, and the cathode electrode may be formed on the anodeelectrode, which is exposed through the opening of the pixel defininglayer. The hole transport layer and the organic light-emitting layer maybe formed using, for example, an inkjet print method or a nozzle printmethod.

A lyophilic surface processing layer may be formed on the anodeelectrode, for example, to improve wettability of a hole transport layersolution. However, when the hole transport layer solution is ejectedonto the surface processing layer, the solution may errantly spreadtoward an adjacent pixel due to its ejection pressure and speed.

As a result, the hole transport layer may be formed up to part of theadjacent pixel. The organic light-emitting layer may also be formed onthe hole transport layer up to part of the adjacent pixel. Therefore,organic light-emitting layers that emit light of different colors mayoverlap each other in adjacent pixels. Consequently, an unwanted mixedcolor may be displayed, to thereby degrade display quality.

SUMMARY

In accordance with one or more embodiments, a light-emitting displaydevice includes a pixel defining layer on the substrate to define eachpixel, the pixel defining layer having an opening to expose the firstelectrode; a charge injection layer on the first electrode; a surfaceprocessing layer on the charge injection layer, the surface processinglayer extending from inside the opening of the pixel defining layer to atop surface of the pixel defining layer, the surface processing layerincluding a plurality of grooves in a portion extending on the topsurface of the pixel defining layer; a charge transport layer on thesurface processing layer; a light-emitting layer on the charge transportlayer; and a second electrode on the light-emitting layer.

The grooves may be on at least one side of the opening along a firstdirection, and the first direction may be toward an adjacent pixel whichemits light of a different color from a color of light emitted from apixel in which the surface processing layer is formed. The grooves maybe shaped substantially as straight lines that extend along a seconddirection crossing the first direction. The grooves may have widths thatincrease in a direction toward the adjacent pixel. The grooves may havesubstantially equal widths. The grooves may have an oblique shapebetween the first direction and a second direction crossing the firstdirection. The grooves may have a lattice shape.

The pixels may include pixels arranged in a row and that emit light of asame color, and the surface processing layer may be formed in units ofthe pixels. The charge transport layer may be conformally formed alongthe surface processing layer.

In accordance with another embodiment, a light-emitting display devicemay include a substrate including a plurality of pixels; a firstelectrode on the substrate for each pixel; a pixel defining layer on thesubstrate to define each pixel, the pixel defining layer has an openingto expose the first electrode; a first common layer on the firstelectrode; a surface processing layer on the first common layer, thesurface processing layer extending from inside the opening of the pixeldefining layer to a top surface of the pixel defining layer, the surfaceprocessing layer including a plurality of grooves in a portion extendingon the top surface of the pixel defining layer; a light-emitting layeron the surface processing layer; and a second electrode on thelight-emitting layer.

The grooves may be on at least one side of the opening in a firstdirection, and the first direction may be toward an adjacent pixel whichemits light of a different color from a color of light emitted from apixel in which the surface processing layer is formed. The grooves maybe shaped substantially in straight lines that extend along a seconddirection crossing the first direction. The grooves may have an obliqueshape between the first direction and a second direction crossing thefirst direction. The grooves may have a lattice shape.

The pixels may include pixels arranged in a row and that emit light of asame color, and the surface processing layer may be formed in units ofthe pixels. The light-emitting layer may be conformally formed along thesurface processing layer.

In accordance with another embodiment, a method for manufacturing alight-emitting display device includes forming a first electrode foreach of a plurality of pixels on a substrate; forming a pixel defininglayer on the substrate to define each of the pixels, the pixel defininglayer having an opening to expose the first electrode of each of thepixels; forming a charge injection layer on the first electrode; forminga surface processing layer on the charge injection layer, the surfaceprocessing layer extending from inside the opening of the pixel defininglayer to a top surface of the pixel defining layer and having aplurality of grooves in a portion extending on the top surface of thepixel defining layer; forming a charge transport layer on the surfaceprocessing layer; forming a light-emitting layer on the charge transportlayer; and forming a second electrode on the light-emitting layer.

The operation of forming the charge transport layer may includeproviding a charge transport layer solution into the opening of thepixel defining layer and drying the charge transport layer solution, andthe operation of forming the light-emitting layer may include providinga light-emitting layer solution into the opening of the pixel defininglayer and drying the light-emitting layer solution. The charge transportlayer solution and the light-emitting layer solution may include a samesolvent. The charge injection layer and the light-emitting layer may beformed using an inkjet print method or a nozzle print method.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates an embodiment of pixels of a light-emitting displaydevice;

FIG. 2 illustrates a view along section line A-A in FIG. 1;

FIG. 3 illustrates an embodiment of a surface processing layer;

FIG. 4 illustrates an embodiment of a method for ejecting a first chargetransport layer solution onto the surface processing layer;

FIG. 5 illustrates an embodiment of a first charge transport layer;

FIGS. 6-12 illustrate various embodiments of a surface processing layer;

FIG. 13 illustrates a light-emitting display device of anotherembodiment;

FIG. 14 illustrates a light-emitting display device of anotherembodiment;

FIG. 15 illustrates a light-emitting display device of anotherembodiment; and

FIGS. 16-24 illustrate an embodiment of a method for manufacturing alight-emitting display device.

DETAILED DESCRIPTION

Example embodiments are described more fully hereinafter with referenceto the accompanying drawings; however, they may be embodied in differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully conveyexemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

FIG. 1 illustrates a plurality of pixels PX of a light-emitting displaydevice 100 according to one embodiment, and FIG. 2 is a cross-sectionalview along line A-A in FIG. 1. Referring to FIGS. 1 and 2, thelight-emitting display device 100 includes a substrate 105, a firstelectrode 110, a pixel defining layer 120, a first charge injectionlayer 130, a surface processing layer 140, a first charge transportlayer 150, a light-emitting layer 160, a second charge transport layer170, a second charge injection layer 180, and a second electrode 190.These members are sequentially stacked in a predetermined (e.g., Z)direction in FIG. 2.

The substrate 105 includes a display area DA and a non-display area NDA.The pixels PX are in the display area DA, and the non-display area NDAis outside the display area DA. The pixels PX may include, for example,red pixels (or sub-pixels) R that emit red light, green pixels (orsub-pixels) G that emit green light, and blue pixels (or sub-pixels) Bthat emit blue light. In FIG. 1, pixels PX that emit light of the samecolor are arranged in a row along a predetermined (e.g., Y) direction,and pixels PX that emit light of different colors are alternatelyarranged in a row along a predetermined (e.g., X) direction. Thearrangement of pixels PX may be different in other embodiments.

When the pixels PX that emit light of the same color are arranged in arow, a first charge transport layer solution 150 a (see FIG. 4) and alight-emitting layer solution may be ejected in one direction, when thefirst charge transport layer 150 and the light-emitting layer 160 areformed using an inkjet print method or a nozzle print method. Therefore,the ejection process may be performed easily. For example, the inkjetprint method may dispense a solution to be printed at a desired positionin the form of ink droplets. The nozzle print method may cause asolution to be printed to flow along a line including a desiredposition.

The substrate 105 may include an insulating substrate. The insulatingsubstrate may include, for example, a transparent glass materialcontaining SiO₂ as a main component. In one embodiment, the insulatingsubstrate may include an opaque or plastic material. The insulatingsubstrate may be, for example, a flexible substrate.

The substrate 105 may include or support other structures formed on theinsulating substrate. Examples include various types of wiring,electrodes, and insulating layers. In one embodiment, the substrate 105may include a plurality of thin-film transistors (TFTs) on theinsulating substrate. Drain electrode of each TFT may be electricallyconnected to a first electrode 110. Also, each TFT may include an activeregion that includes, for example, amorphous silicon, polycrystallinesilicon, or monocrystalline silicon. In another embodiment, each TFT mayinclude an active region that includes an oxide semiconductor.

The first electrode 110 is formed on the substrate 105 in each pixel PX.The first electrode 110 may be an anode electrode, which provides holesto the light-emitting layer 160 in response to a signal transmitted to acorresponding TFT, or a cathode electrode, which provides electrons tothe light-emitting layer 160 in response to the signal transmitted tothe TFT. The first electrode 110 may be used as a transparent electrodeor a reflective electrode. When used as a transparent electrode, thefirst electrode 110 may include, for example, indium tin oxide (ITO),indium zinc oxide (IZO), zinc oxide (ZnO), or In₂O₃. When used as areflective electrode, the first electrode 110 may include a reflectivelayer using Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound of thesame, and may include ITO, IZO, ZnO or In₂O₃ on the reflective layer.The first electrode 110 may be formed by, but not limited to, aphotolithography process.

The pixel defining layer 120 defines each pixel PX on the substrate 105and has an opening OP that exposes the first electrode 110. Accordingly,the first charge injection layer 130 is formed on the first electrode110 through the opening OP of the pixel defining layer 120. The pixeldefining layer 120 may include an insulating material. For example, thepixel defining layer 120 may include at least one organic material,e.g., benzocyclobutene (BCB), polyimide (PI), polyamide (PA), acrylicresin, or phenolic resin. In another example, the pixel defining layer120 may include an inorganic material, e.g., silicon nitride. The pixeldefining layer 120 may be formed, for example, by a photolithographyprocess or another process.

In the current embodiment, the pixel defining layer 120 includes aninsulating material that causes a contact angle of the first chargetransport layer solution 150 a (see, e.g., FIG. 4) relative to the pixeldefining layer 120 and a contact angle of the first charge transportlayer solution 150 a (see, e.g., FIG. 4) relative to the surfaceprocessing layer 140 to be different when the first charge transportlayer 150 is formed using an inkjet print method or nozzle print method.

For example, the pixel defining layer 120 may include an insulatingmaterial that causes the contact angle of the first charge transportlayer solution 150 a relative to the pixel defining layer 120 to begreater than the contact angle of the first charge transport layersolution 150 a relative to the surface processing layer 140. In oneembodiment, the pixel defining layer 120 may include an insulatingmaterial that causes the contact angle of the first charge transportlayer solution 150 a relative to the pixel defining layer 120 to be 40degrees or more.

The first charge injection layer 130 may be on the first electrode 110exposed through the opening OP of the pixel defining layer 120 toentirely cover the pixel defining layer 120. The first charge injectionlayer 130 may be a hole injection layer receiving holes from the firstelectrode 120, or an electron injection layer receiving electrons fromthe first electrode 120. A case where the first charge injection layer130 is a hole injection layer will be described as an example.

The first charge injection layer 130 is a buffer layer that lowers anenergy barrier between the first electrode 110 and the first chargetransport layer 150. The first charge injection layer 130 facilitatesinjection of holes from the first electrode 110 to the first chargetransport layer 150. The first charge injection layer 130 may include,for example, an organic compound such as but not limited to4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (MTDATA), copperphthalocyanine (CuPc), or poly(3,4-ethylenedioxythiphene, polystyrenesulfonate) (PEDOT/PSS). The first charge injection layer 130 may becoated, for example, by a slit coating process.

The surface processing layer 140 is formed on the first charge injectionlayer 130 in each pixel PX. The surface processing layer 140 may beformed, for example, on the first charge injection layer 130 to extendfrom inside the opening OP of the pixel defining layer 120 to a topsurface of the pixel defining layer 120. The surface processing layer140 may have a plurality of grooves g1 in a portion extending on the topsurface of the pixel defining layer 120. The surface processing layer140 may be formed, for example, by a photolithography process.

The surface processing layer 140 may include a conductive primer thatcauses the surface processing layer 140 to be more lyophilic to thefirst charge transport layer solution 150 a (see, e.g., FIG. 4) than thepixel defining layer 120, e.g., causes the contact angle of the firstcharge transport layer solution 150 a (see FIG. 4) relative to thesurface processing layer 140 to be smaller than the contact angle of thefirst charge transport layer solution 150 a (see, e.g., FIG. 4) relativeto the pixel defining layer 120.

For example, the surface processing layer 140 may include a conductiveprimer that causes the contact angle of the first charge transport layersolution 150 a relative to the surface processing layer 140 to be 20degrees or less. In this case, when the first charge transport layersolution 150 a is ejected onto the surface processing layer 140 (insidethe opening OP of the pixel defining layer 120 in each pixel PX) usingan inkjet print method or nozzle print method, the first chargetransport layer solution 150 a may be stably confined within thecorresponding pixel PX without spreading to the exposed top surface ofthe pixel defining layer 120 (e.g., due to high wettability of the firstcharge transport layer solution 150 a relative to the surface processinglayer 140). Also, the first charge transport layer 150 may be uniformlyformed on the surface processing layer 140. The qualify of highwettability may mean, for example, that a liquid is widely spread overthe surface of a solid to contact a wide area of the surface.

The first charge transport layer 150 is formed on the surface processinglayer 140. The first charge transport layer 150 may be conformallyformed along the surface processing layer 140 having the grooves g1. Thefirst charge transport layer 150 at least partially fills the grooves g1of the surface processing layer 140.

The first charge transport layer 150 may be a hole transport layerreceiving holes from the first charge injection layer 130 via thesurface processing layer 140, or an electron transport layer receivingelectrons from the first charge injection layer 130 via the surfaceprocessing layer 140. A case where the first charge transport layer 130is a hole transport layer will be described as an example.

The first charge transport layer 150 may transport holes from the firstcharge injection layer 130 via the surface processing layer 140 to thelight-emitting layer 160. The first charge transport layer 150 mayinclude, for example, an organic compound such as but not limited toN,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-bi-phenyl-4,4′-diamine (TPD)or N,N′-di(naphthalen-1-yl)-N,N′-diphenyl-benzidine (NPB). The firstcharge transport layer 150 may be formed, for example, using an inkjetprint method or nozzle print method.

The light-emitting layer 160 is formed on the first charge transportlayer 150. The light-emitting layer 160 emits light when holes from thefirst electrode 110 and electrons from the second electrode 190recombine. The holes and electrons provided to the light-emitting layer160 combine to form excitons. When the excitons change from an excitedstate to a ground state, the light-emitting layer 160 emits light. Thelight-emitting layer 160 may include, for example, a red light-emittinglayer to emit red light, a green light-emitting layer to emit greenlight, and a blue light-emitting layer to emit blue light. Thelight-emitting layer 160 may be formed, for example, using an inkjetprint method or nozzle print method.

The red light-emitting layer may include one red light-emitting materialor a host and a red dopant. Examples of the host of the redlight-emitting layer include but are not limited to Alq₃,4,4′-N,N′-dicarbazol-biphenyl (CBP), poly(n-vinylcarbazole) (PVK),9,10-Di(naphthyl-2-yl)anthracene (ADN),4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI),3-tert-butyl-9,10-di(naphth-2-yl) anthracene (TBADN), terfluorene (E3),distyrylarylene (DSA). In addition, examples of the red dopant includebut are not limited to PtOEP, Ir(piq)₃ and Btp₂Ir(acac).

The green light-emitting layer may include one green light-emittingmaterial or a host and a green dopant. The host of the redlight-emitting layer may be used as the host of the green light-emittinglayer. Examples of the green dopant may include but are not limited toIr(ppy)₃, Ir(ppy)₂(acac) and Ir(mpyp)₃.

The blue light-emitting layer may include one blue light-emittingmaterial or a host and a blue dopant. The host of the red light-emittinglayer may be used as the host of the blue light-emitting layer. Examplesof the blue dopant include but are not limited to F₂Irpic,(F₂ppy)₂Ir(tmd), Ir(dfppz)₃, ter-fluorene,4,4′-bis(4-diphenylaminostyryl) biphenyl (DPAVBi),2,5,8,11-tetra-ti-butyl pherylene (TBPe).

The second charge transport layer 170 may be formed on thelight-emitting layer 160. The second charge transport layer 170 may bean electron transport layer receiving electrons from the secondelectrode 190 via the second charge injection layer 180, or a holetransport layer receiving holes from the second electrode 190 via thesecond charge injection layer 180. A case where the second chargetransport layer 170 is an electron transport layer will be described asan example.

The second charge transport layer 170 may transport electrons from thesecond electrode 190 via the second charge injection layer 180 to thelight-emitting layer 160. The second charge transport layer 170 mayinclude, for example, an organic compound such as but not limited to4,7-diphenyl-1,10-phenanthroline) (Bphen), BAlq,tris(8-quinolinorate)aluminum (Alq3),berylliumbis(benzoquinolin-10-olate) (Bebq₂), or TPBI. The second chargetransport layer 170 may be formed, for example, by a deposition process.

The second charge injection layer 180 may be formed on the second chargetransport layer 170. The second charge injection layer 180 may be anelectron injection layer receiving electrons from the second electrode190, or a hole injection layer receiving holes from the second electrode190. A case where the second charge injection layer 180 is an electroninjection layer will be described as an example.

The second charge injection layer 180 is a buffer layer that lowers anenergy barrier between the second charge transport layer 170 and thesecond electrode 190. The second charge injection layer 180 facilitatesthe injection of electrons from the second electrode 190 to the secondcharge transport layer 170. The second charge injection layer 180 mayinclude, for example, LiF or CsF. The second charge injection layer 180may be formed, for example, by a deposition process.

The second electrode 190 may be formed on the second charge injectionlayer 180. The second electrode 190 may be a cathode electrode providingelectrons to the light-emitting layer 160 or an anode electrodeproviding holes to the light-emitting layer 160. Like the firstelectrode 110, the second electrode 190 may be used as a transparentelectrode or a reflective electrode. The second electrode 190 may beformed, for example, by a deposition process.

The light-emitting display device 100 may further include anencapsulation substrate on the second electrode 190. The encapsulationsubstrate may be an insulating substrate. A spacer may be between thesecond electrode 190 on the pixel defining layer 120 and theencapsulation substrate. The encapsulation layer made of an insulatingmaterial may cover and thus protect the entire structure. In otherembodiments, the encapsulation substrate may be omitted.

FIG. 3 illustrates an embodiment of a surface processing layer, which,for example, may correspond to the surface processing layer 140 in FIG.2. FIG. 4 illustrates an example of a method for ejecting the firstcharge transport layer solution 150 a onto the surface processing layer140 in FIG. 3. FIG. 5 is a cross-sectional view of the first chargetransport layer 150 formed by drying the charge transport layer solution150 a in FIG. 4.

Referring to FIG. 3, the surface processing layer 140 has the grooves g1in at least one side portion thereof. The grooves g1 may be on at leastone side of the opening OP of the pixel defining layer 120. A directionof one side portion or one side may be a first direction D1 toward anadjacent pixel PX, which emits light of a color different from the colorof light emitted from a corresponding pixel PX in which the surfaceprocessing layer 140 is formed. For example, in the case where a redpixel R emitting red light and a green pixel G emitting green light areadjacent to each other, the surface processing layer 140 formed in thered pixel R has the grooves g1 in a side portion thereof in a directionin which the green pixel G is disposed. In FIG. 3, the grooves g1 areformed in two side portions of the surface processing layer 140, basedon the assumption that pixels PX emitting light of different colors aredisposed on two sides of one pixel PX.

The grooves g1 may be shaped, for example, in straight lines that extendalong a second direction D2 crossing or perpendicular to the firstdirection D1 toward the adjacent pixel PX. The grooves g1 form roughnessat an edge of the surface processing layer 140. Accordingly, when thefirst charge transport layer solution 150 a is ejected from an ejectiondevice 10 onto the surface processing layer 140 using, e.g., a nozzleprint method, the grooves g1 of the surface processing layer 140 mayincrease the contact angle of the first charge transport layer solution150 a relative to the edge of the surface processing layer 140. As aresult, the first charge transport layer solution 150 a may be confinedin the grooves g1, and thus the first charge transport layer solution150 a is prevented from spreading beyond the surface processing layer140.

For example, the grooves g1 of the surface processing layer 140 mayincrease resistance to a force F (e.g., generated by ejection pressureand ejection speed) with which the first charge transport layer solution150 a ejected from the ejection device 10 spreads beyond the surfaceprocessing layer 140. This may confine the first charge transport layersolution 150 a in the grooves g1 while preventing the first chargetransport layer solution 150 a from spreading beyond the surfaceprocessing layer 140. Thus, it is possible to reduce or prevent thefirst charge transport layer solution 150 a from flowing to an adjacentpixel PX (for example, a pixel PX that emits light of a different color)and unwantedly spreading to part of the adjacent pixel PX.

In one embodiment, the widths w1, w2, or w3 of the grooves g1 mayincrease toward an adjacent pixel PX. The grooves g1 may thereforereduce or prevent a sharp increase in the contact angle of the firstcharge transport layer solution 150 a relative to the edge of thesurface processing layer 140. As a result, the first charge transportlayer solution 150 a may spread over a large area of the surfaceprocessing layer 140. Accordingly, when the first charge transport layersolution 150 a ejected onto the surface processing layer 140 dries toform the first charge transport layer 150 as in FIG. 5, the first chargetransport layer 150 may be formed over a large area of the surfaceprocessing layer 140.

The first charge transport layer 150, formed by the drying of the firstcharge transport layer solution 150 a, forms pinning points P with thesurface processing layer 140 as illustrated in FIG. 5. In this case, thelight-emitting layer 160 may be formed to be aligned with the pinningpoints P by ejecting a light-emitting layer solution, which contains thesame solvent as the first charge transport layer solution 150 a, ontothe first charge transport layer 150 using an inkjet print method ornozzle print method, and drying the light-emitting layer solution. Thus,edges of the light-emitting layer 160 may be aligned with the edges ofthe first charge transport layer 150.

FIGS. 6 through 12 illustrate various embodiments of the surfaceprocessing layer 140. Referring to FIG. 6, a surface processing layer140 a includes a plurality of grooves g2 having a lattice shape in atleast one side portion thereof. The grooves g2 are formed by orthogonalintersection of first grooves g21 and second grooves g22. The firstgrooves g21 are shaped in straight lines that extend along a seconddirection D2 crossing or perpendicular to a first direction D1 toward anadjacent pixel PX. The second grooves g22 are shaped in straight linesthat extend along the first direction D1. The first grooves g21 maybecome wider along the first direction D1.

When a force F (with which a first charge transport layer solutionejected onto the surface processing layer 140 a by moving an ejectiondevice 10 spreads beyond the surface processing layer 140 a) isgenerated in the first direction D1 and a diagonal direction between thefirst direction D1 and the second direction D2, the grooves g2 mayeffectively prevent the first charge transport layer solution fromspreading along not only the first direction D1 but also the diagonaldirection.

Referring to FIG. 7, a surface processing layer 140 b includes aplurality of oblique grooves g3 in at least one side portion thereof.The grooves g3 are formed obliquely between a first direction D1 towardan adjacent pixel PX and a second direction D2 crossing or perpendicularto the first direction D1. The grooves g3 may have equal widths.

When a force F (with which a first charge transport layer solutionejected onto the surface processing layer 140 b by moving an ejectiondevice 10 spreads beyond the surface processing layer 140 b) isgenerated in the first direction D1 and a diagonal direction between thefirst direction D1 and the second direction D2, the grooves g3 mayeffectively prevent the first charge transport layer solution fromspreading along not only the first direction D1, but also the diagonaldirection.

Referring to FIG. 8, a surface processing layer 140 c includes aplurality of grooves g4 formed obliquely in different directions in bothside portions thereof. For example, the grooves g4 include first groovesg41 and second grooves g42. The first grooves g41 are formed to have afirst oblique shape between a first direction D1 toward an adjacentpixel PX and a second direction D2 crossing or perpendicular to thefirst direction D1. The second grooves g42 are formed to have a secondoblique shape which is symmetrical to the first oblique shape withrespect to the second direction D2.

When a force F (with which a first charge transport layer solutionejected onto the surface processing layer 140 c by moving an ejectiondevice 10 spreads beyond the surface processing layer 140 c) isgenerated in a diagonal direction between the first direction D1 and thesecond direction D2 at one side portion of the surface processing layer140 c, the first oblique shape is orthogonal to the diagonal direction.Accordingly, the first grooves g41 having the first oblique shape mayeffectively reduce or prevent the first charge transport layer solutionfrom spreading from the side portion of the surface processing layer 140c in the diagonal direction between the first direction D1 and thesecond direction D2.

When the force F (with which the first charge transport layer solutionejected onto the surface processing layer 140 c by moving the ejectiondevice 10 spreads beyond the surface processing layer 140 c) isgenerated in a diagonal direction between the first direction D1 and thesecond direction D2 at the other side portion of the surface processinglayer 140 c, the second oblique shape is orthogonal to the diagonaldirection. Accordingly, the second grooves g42 having the second obliqueshape may effectively prevent the first charge transport layer solutionfrom spreading from the side portion of the surface processing layer 140c in the diagonal direction between the first direction D1 and thesecond direction D2.

Thus, when the force F (with which the first charge transport layersolution ejected onto the surface processing layer 140 c by moving theejection device 10 spreads beyond the surface processing layer 140 c) isgenerated in diagonal directions between the first direction D1 and thesecond direction D2, the grooves g4 may effectively reduce or preventthe first charge transport layer solution from spreading in differentdiagonal directions.

Referring to FIG. 9, a surface processing layer 140 d includes aplurality of grooves g5 having a lattice shape. The grooves g5 areformed by orthogonal intersection of first oblique grooves g51 andsecond oblique grooves g52 in at least one side portion thereof. Evenwhen a movement start point of an ejection device 10 changes, thegrooves g5 may effectively reduce or prevent a first charge transportlayer solution from spreading, not only in a first direction D1 but alsoin a diagonal direction between the first direction D1 and a seconddirection D2.

Referring to FIG. 10, a surface processing layer 140 e includes aplurality of grooves g6 having equal widths in at least one side portionthereof. The surface processing layer 140 e having the grooves g6 may beapplied in a limited space, for example, in a case where there is a finepitch between adjacent pixels PX.

Referring to FIG. 11, a surface processing layer 140 f is formed inunits of pixels PX that are arranged in a row and emit light of the samecolor. For example, the surface processing layer 140 f may be formed inevery two or more pixels PX to be larger in size than the surfaceprocessing layer 140 of FIG. 3. However, the surface processing layer140 f may be formed in the same shape as the surface processing layer140 to have a plurality of grooves g7 extending along a second directionD2 crossing or perpendicular to a first direction D1 toward an adjacentpixel PX which emits light of a different color. When formed by aphotolithography process, the surface processing layer 140 f mayfacilitate a patterning process.

Referring to FIG. 12, a surface processing layer 140 g includes aplurality of grooves g8 in all side portions thereof. The grooves g8 areformed in the same shape as the grooves g1 of the surface processinglayer 140 of FIG. 3. When pixels PX emitting light of different colorsare disposed on all sides of a pixel PX, the grooves g8 may prevent afirst charge transport layer solution from spreading in all directionsfrom the surface processing layer 140 g when the first charge transportlayer solution is ejected onto the surface processing layer 140 g usingan inkjet print method.

As described above, each of the light-emitting devices according to theaforementioned embodiments include a surface processing layer (140, 140a through 140 g) having roughness formed on an edge thereof by aplurality of grooves (g1 through g8). The roughness increases resistanceto a force F (e.g., generated by ejection pressure and ejection speed)with which a first charge transport layer solution (150 a) ejected ontothe surface processing layer (140, 140 a through 140 g) using an inkjetprint method or nozzle print method spreads beyond the surfaceprocessing layer (140, 140 a through 140 g). This may reduce or preventthe first charge transport layer solution (150 a) from spreading beyondthe surface processing layer (140, 140 a through 140 g).

Accordingly, the light-emitting display devices according to the one ormore embodiments may reduce or prevent the first charge transport layersolution (150 a) from spreading to an adjacent pixel PX, for example, apixel PX that emits light of a different color and unwantedly forming afirst charge transport layer (150) up to part of the adjacent pixel PX.

Therefore, the light-emitting display devices according to one or moreembodiments may prevent a light-emitting layer (160) from being formedon the first charge transport layer (150) up to part of the adjacentpixel PX, thereby avoiding a situation where light-emitting layersemitting light of different colors overlap each other in adjacent pixelsPX. Consequently, this may reduce or prevent degradation of displayquality due to the display of an unwanted mixed color on thelight-emitting display devices being driven.

FIG. 13 is a cross-sectional view of another embodiment of alight-emitting display device 200, which may have the same configurationas the light-emitting display device 100 in FIG. 2 except for a firstcharge transport layer 250 and a light-emitting layer 260.

The first charge transport layer 250 is similar to the first chargetransport layer 150 of FIG. 2. However, the first charge transport layer250 is not formed up to edges of a surface processing layer 140, butrather fills one or more of a plurality of grooves g1. When a firstcharge transport layer solution is ejected onto the surface processinglayer 140 using an inkjet print method or nozzle print method to formthe first charge transport layer 250, if the ejection pressure is low,the first charge transport layer solution may not spread to the edges ofthe surface processing layer 140. As a result, the above structure maybe formed.

The light-emitting layer 260 is similar to the light-emitting layer 160of FIG. 2. Here, the light-emitting layer 260 is formed on the firstcharge transport layer 250 and extends up to the edges of the surfaceprocessing layer 140. This structure may be formed because the surfaceprocessing layer 140 is lyophilic, not only to the first chargetransport layer solution but also to a light-emitting layer solution,when the light-emitting layer solution has the same solvent as the firstcharge transport layer solution. The grooves g2 through g7 in theembodiments of FIGS. 6 through 12 may be applied to the grooves g1 ofthe surface processing layer 140.

Like the light-emitting display device 100, the light-emitting displaydevice 200 includes the surface processing layer 140 having the groovesg1 in at least one side thereof. The surface processing layer 140 havingthe grooves g1 prevents the light-emitting layer 260 from being formedon the first charge transport layer 250 up to part of an adjacent pixelPX, thereby avoiding a situation where light-emitting layers emittinglight of different colors overlap each other in adjacent pixels PX. Thismay prevent degradation of display quality due to the display of anunwanted mixed color on the light-emitting display device 200 beingdriven.

FIG. 14 is a cross-sectional view of another embodiment of alight-emitting display device 300, which may have the same configurationas the light-emitting display device 100 of FIG. 2 except a first chargetransport layer 350 and a light-emitting layer 360.

The first charge transport layer 350 is similar to the first chargetransport layer 150 of FIG. 2. However, the first charge transport layer350 is formed on a surface processing layer 140, but not on the surfaceprocessing layer 140 between a plurality of grooves g1. For example, aheight of the first charge transport layer 350 in the grooves g1 may beequal to or less than a height of the grooves g1. This structure may beformed when a first charge transport layer solution in the grooves g1 ofthe surface processing layer 140 dries, after being ejected onto thesurface processing layer 140 using an inkjet print method or nozzleprint method, to form the first charge transport layer 350.

The light-emitting layer 360 is similar to the light-emitting layer 160of FIG. 2. However, the light-emitting layer 360 is formed on the firstcharge transport layer 350, and contacts the surface processing layer140 in the grooves g1 of the surface processing layer 140. Thisstructure may be formed because the surface processing layer 140 islyophilic, not only to the first charge transport layer solution butalso to a light-emitting layer solution, when the light-emitting layersolution has the same solvent as the first charge transport layersolution.

The grooves g2 through g7 in the embodiments of FIGS. 6 through 12 maybe applied to the grooves g1 of the surface processing layer 140.

The light-emitting device 300 according to the current embodiment, likethe light-emitting display device 100, includes the surface processinglayer 140 having the grooves g1 in at least one side thereof. Thesurface processing layer 140 having the grooves g1 prevents thelight-emitting layer 360 from being formed on the first charge transportlayer 350 up to part of an adjacent pixel PX, thereby avoiding asituation where light-emitting layers emitting light of different colorsoverlap each other in adjacent pixels PX. This may reduce or preventdegradation of display quality due to the display of an unwanted mixedcolor on the light-emitting display device 300 being driven.

FIG. 15 is a cross-sectional view of another embodiment of alight-emitting display device 400 which includes a substrate 105, afirst electrode 110, a pixel defining layer 420, a first common layer430, a surface processing layer 440, a light-emitting layer 450, asecond common layer 460, and a second electrode 470.

The pixel defining layer 420 is similar to the pixel defining layer 120of FIG. 2. However, the pixel defining layer 420 may include aninsulating material that causes a contact angle of a light-emittinglayer solution relative to the pixel defining layer 420 and a contactangle of the light-emitting layer solution relative to the surfaceprocessing layer 440 to be different, when the light-emitting layer 450is formed using an inkjet print method or nozzle print method.

For example, the pixel defining layer 420 may include an insulatingmaterial that causes the contact angle of the light-emitting layersolution relative to the pixel defining layer 420 to be greater than thecontact angle of the light-emitting layer solution relative to thesurface processing layer 440. In one embodiment, the pixel defininglayer 420 may be made of an insulating material that causes the contactangle of the light-emitting layer solution to the pixel defining layer420 to be 40 degrees or more.

The first common layer 430 may be formed on the first electrode 110exposed through an opening OP of the pixel defining layer 420 toentirely cover the pixel defining layer 420. The first common layer 430includes a first charge injection layer. The first charge injectionlayer contacts the first electrode 110. In addition, the first commonlayer 430 may further include a first charge transport layer on thefirst charge injection layer. The first charge injection layer and thefirst charge transport layer may include the same material as the firstcharge injection layer 130 and the first charge transport layer 140 ofFIG. 2.

The surface processing layer 440 has a plurality of grooves g1 in atleast one side portion thereof, and may be similar to the surfaceprocessing layer 140 of FIG. 2. However, the surface processing layer440 may include a conductive primer that causes the surface processinglayer 440 to be more lyophilic to the light-emitting layer solution thanthe pixel defining layer 420, e.g., causes the contact angle of thelight-emitting layer solution relative to the surface processing layer440 to be smaller than the contact angle of the light-emitting layersolution relative to the pixel defining layer 420. In one embodiment,the surface processing layer 440 may include a conductive primer thatcauses the contact angle of the light-emitting layer solution relativeto the surface processing layer 440 to be 20 degrees or less.

Thus, when the light-emitting layer solution is ejected onto the surfaceprocessing layer 440 inside the opening OP of the pixel defining layer420 in each pixel PX by using an inkjet print method or nozzle printmethod, the light-emitting layer solution may be stably confined withinthe corresponding pixel PX without spreading to an exposed top surfaceof the pixel defining layer 420 due to high wettability of thelight-emitting layer solution to the surface processing layer 440. Also,the light-emitting layer 450 may be uniformly formed on the surfaceprocessing layer 440.

The light-emitting layer 450 may be similar to the light-emitting layer160 of FIG. 2. However, the light-emitting layer 450 is formed on thesurface processing layer 440. The light-emitting layer 450 may beconformally formed along the surface processing layer 440 having thegrooves g1 that form roughness. The light-emitting layer 450 at leastpartially fills the grooves g1 of the surface processing layer 440.

Because the light-emitting layer 450 is formed directly on the surfaceprocessing layer 440, when the light-emitting layer solution is ejectedonto the surface processing layer 440 using a nozzle print method toform the light-emitting layer 450, the contact angle of thelight-emitting layer solution relative to an edge of the surfaceprocessing layer 440 may be prevented from increasing. This may preventthe light-emitting layer solution from spreading beyond the surfaceprocessing layer 440, thereby confining the light-emitting layersolution in the grooves g1 of the surface processing layer 440.

The second common layer 460 is formed on the light-emitting layer 450.The second common layer 460 includes a second charge transport layer.The second charge transport layer contacts the light-emitting layer 460.In addition, the second common layer 430 may include a second chargeinjection layer on the second charge transport layer. The second chargetransport layer and the second charge injection layer may include thesame material as the second charge transport layer 170 and the secondcharge injection layer 180 of FIG. 2. The second electrode 470 may beidentical to the second electrode 190 of FIG. 2.

The grooves g2 through g7 in the embodiments of FIGS. 6 through 12 maybe applied to the grooves g1 of the surface processing layer 440.

The light-emitting device 400 according to the current embodiment, likethe light-emitting display device 100, includes the surface processinglayer 440 having the grooves g1 in at least one side thereof. Thesurface processing layer 440 having the grooves g1 prevents thelight-emitting layer 450 from being formed on the surface processinglayer 440 up to part of an adjacent pixel PX, thereby avoiding asituation where light-emitting layers emitting light of different colorsoverlap each other in adjacent pixels PX. This may prevent degradationof display quality due to the display of an unwanted mixed color on thelight-emitting display device 400 being driven.

FIGS. 16 through 24 are cross-sectional views illustrating an embodimentof a method for manufacturing a light-emitting display device. Referringto FIG. 16, a first electrode 110 is formed on a substrate 105 in eachof a plurality of pixels PX (see FIG. 1) defined in the substrate 105.The first electrode 110 may be formed, for example, by depositing atransparent electrode material or a reflective material on the substrate105 and patterning the transparent electrode material or the reflectivematerial.

Referring to FIG. 17, a pixel defining layer 120 is formed on thesubstrate 105 to define each pixel PX (see FIG. 1) and has an opening OPthat exposes the first electrode 110. The pixel defining layer 120 maybe formed, for example, by depositing an insulating material on thewhole surface of the substrate 105 to cover the first electrode 110using a deposition method and patterning the deposited insulatingmaterial.

The pixel defining layer 120 may include an insulating material thatcauses a contact angle of a first charge transport layer solution 150 a(see FIG. 20) relative to the pixel defining layer 120 to be differentfrom a contact angle of the first charge transport layer solution 150 a(see FIG. 4) relative to a surface processing layer 140 (see FIG. 19)when a first charge transport layer 150 is formed using an inkjet printmethod or nozzle print method. For example, the pixel defining layer 120may include an insulating material that causes the contact angle of thefirst charge transport layer solution 150 a (see FIG. 20) relative tothe pixel defining layer 120 to be 40 degrees or more

Referring to FIG. 18, a first charge injection layer 130 is formed onthe first electrode 110. The first charge injection layer 130 may beformed not only on the first electrode 110 but also on the whole surfaceof the pixel defining layer 120 using, e.g., slit coating.

Referring to FIG. 19, the surface processing layer 140 is formed on thefirst charge injection layer 130, to extend from inside the opening OPof the pixel defining layer 120 to a top surface of the pixel defininglayer 120. The surface processing layer 140 may have a plurality ofgrooves g1 in a portion extending on the top surface of the pixeldefining layer 120. The surface processing layer 140 may be formed, forexample, by a photolithography process. The surface processing layer 140may be shaped as illustrated in FIG. 3. The grooves g1 of the surfaceprocessing layer 140 may also be formed as the grooves g2 through g8 asin the embodiments of FIGS. 6 through 13.

The surface processing layer 140 may include a conductive primer thatcauses the surface processing layer 140 to be more lyophilic to thefirst charge transport layer solution 150 a (see FIG. 20) than the pixeldefining layer 120, e.g., causes the contact angle of the first chargetransport layer solution 150 a (see FIG. 20) relative to the surfaceprocessing layer 140 to be smaller than the contact angle of the firstcharge transport layer solution 150 a (see FIG. 20) relative to thepixel defining layer 120. In one embodiment, the surface processinglayer 140 may include a conductive primer that causes the contact angleof the first charge transport layer solution 150 a (see FIG. 20)relative to the surface processing layer 140 to be 20 degrees or less.

Thus, when the first charge transport layer solution 150 a (see FIG. 20)is ejected onto the surface processing layer 140 inside the opening OPof the pixel defining layer 120 in each pixel PX using an inkjet printmethod or nozzle print method, the first charge transport layer solution150 a (see FIG. 20) may be stably confined within the correspondingpixel PX, without spreading to the exposed top surface of the pixeldefining layer 120 due to high wettability of the first charge transportlayer solution 150 a (see FIG. 20) relative to the surface processinglayer 140. The first charge transport layer 150 (see FIG. 21) may beuniformly formed on the surface processing layer 140.

Referring to FIGS. 20 and 21, the first charge transport layer 150 isformed on the surface processing layer 140. For example, referring toFIG. 20, the first charge transport layer solution 150 a is ejected froman ejection device 10 into the opening OP of the pixel defining layer120 using an inkjet print method or nozzle print method. Here, theejection pressure and ejection speed of the ejection device 10 maygenerate a large force F with which the first charge transport layersolution 150 a spreads beyond the surface processing layer 140. As aresult, the first charge transport layer solution 150 a may spread froman edge of the surface processing layer 140.

However, the grooves g1 that form roughness at the edge of the surfaceprocessing layer 140 may increase resistance to the force F. Theincreased resistance may prevent the first charge transport layersolution 150 a from spreading beyond the surface processing layer 140,thus confining the first charge transport layer solution 150 a in thegrooves g1.

Referring to FIG. 21, the first charge transport layer solution 150 a isdried to form the first charge transport layer 150, which forms pinningpoints P with the surface processing layer 140, on the surfaceprocessing layer 140. The first charge transport layer 150 may beconformally formed along the surface processing layer 140 having thegrooves g1.

Referring to FIGS. 22 and 23, a light-emitting layer 160 is formed onthe first charge transport layer 150. For example, referring to FIG. 22,a light-emitting layer solution 160 a is ejected from an ejection device20 into the opening OP of the pixel defining layer 120 using an inkjetprint method or nozzle print method. Here, the light-emitting layersolution 160 a may contain the same solvent as the first chargetransport layer solution 150 a of FIG. 20. In this case, the firstcharge transport layer 150 may become lyophilic to the light-emittinglayer solution 160 a, and the light-emitting layer solution 160 a, whenejected onto the first charge transport layer 150, may be prevented fromspreading beyond the first charge transport layer 150 to the exposed topsurface of the pixel defining layer 120.

Referring to FIG. 23, the light-emitting layer solution 160 a is driedto form the light-emitting layer 160 on the first charge transport layer150.

Referring to FIG. 24, a second transport layer 170, a second chargeinjection layer 180, and a second electrode 190 are formed on thelight-emitting layer 160. The second charge transport layer 170, thesecond charge injection layer 180 and the second electrode 190 may beformed, for example, by a deposition process.

The method of manufacturing a light-emitting display device according tothe current embodiment may further include placing an encapsulationsubstrate on the second electrode 190. In addition, the method ofmanufacturing a light-emitting display device according to the currentembodiment may include placing a spacer between the second electrode 190and the encapsulation substrate. Various methods may be used for placingthe encapsulation substrate and the spacer.

Embodiments of the present invention provide at least one of thefollowing advantages. A light-emitting display device according to oneembodiment includes a surface processing layer having roughness formedon an edge thereof by a plurality of grooves. The surface processinglayer having roughness may prevent a first charge transport layersolution ejected onto the surface processing layer using an inkjet printmethod or a nozzle print method from spreading beyond the surfaceprocessing layer. Accordingly, this may prevent the first chargetransport layer solution from spreading toward an adjacent pixel whichemits light of a different color and thus unwantedly forming a firstcharge transport layer up to part of the adjacent pixel.

Therefore, the light-emitting display device according to at least oneembodiment may prevent a light-emitting layer from being formed on thefirst charge transport layer up to part of the adjacent pixel, therebyavoiding a situation where light-emitting layers emitting light ofdifferent colors overlap each other in adjacent pixels. As a result,this can prevent degradation of display quality due to the display of anunwanted mixed color on the light-emitting display device being driven.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of skill in the art as of thefiling of the present application, features, characteristics, and/orelements described in connection with a particular embodiment may beused singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwiseindicated. Accordingly, it will be understood by those of skill in theart that various changes in form and details may be made withoutdeparting from the spirit and scope of the present invention as setforth in the following claims.

What is claimed is:
 1. A light-emitting display device, comprising: asubstrate including a plurality of pixels; a first electrode on thesubstrate for each pixel; a pixel defining layer on the substrate todefine each pixel, the pixel defining layer having an opening to exposethe first electrode; a surface processing layer including a firstportion on the first electrode and a second portion on the pixeldefining layer, the surface processing layer including a plurality ofgrooves on the second portion and the grooves not overlapping with theopening; a light-emitting layer on the surface processing layer; and asecond electrode on the light-emitting layer.
 2. The device as claimedin claim 1, wherein the first portion is connected to the secondportion.
 3. The device as claimed in claim 1, wherein: the grooves areon at least one side of the opening along a first direction, and thefirst direction is toward an adjacent pixel which emits light of adifferent color from a color of light emitted from a pixel in which thesurface processing layer is formed.
 4. The device as claimed in claim 3,wherein the grooves are shaped substantially as straight lines thatextend along a second direction crossing the first direction.
 5. Thedevice as claimed in claim 3, wherein the grooves have widths thatincrease in a direction toward the adjacent pixel.
 6. The device asclaimed in claim 3, wherein the grooves have substantially equal widths.7. The device as claimed in claim 3, wherein the grooves have an obliqueshape between the first direction and a second direction crossing thefirst direction.
 8. The device as claimed in claim 3, wherein thegrooves have a lattice shape.
 9. The device as claimed in claim 3,wherein: the pixels include pixels arranged in a row and that emit lightof a same color, and the surface processing layer is formed in units ofthe pixels.
 10. The device as claimed in claim 1, further comprising: acharge injection layer between the first electrode and the surfaceprocessing layer; and a charge transport layer between the surfaceprocessing layer and the light-emitting layer.
 11. The device as claimedin claim 10, wherein the charge transport layer is conformally formedalong the surface processing layer.
 12. The device as claimed in claim10, at least a portion of the charge transport layer is filled in thegrooves.
 13. The device as claimed in claim 1, wherein thelight-emitting layer is interposed between the surface processing layerand the second electrode.